Definition & Overview

Double vision, also referred to in medical terms as diplopia, is due to the misalignment of the eyes causing the sufferer to see two images of a single object adjacent to each other. It should be considered as a serious condition and requires immediate diagnosis and treatment as some cases are considered life-threatening.

A person with double vision will notice that the entire image is usually blurred due to objects overlapping one another. In some cases, vision may improve by holding the object towards or away from the face, squinting, or increasing light in the room. However, improving the view may not be possible for some people.

Diplopia can affect one or both eyes. If the condition affects both eyes, it is referred to as binocular diplopia otherwise; it is referred to as monocular diplopia. This is less common than the other type and is usually the result of an abnormality of the affected eye. Since the problem occurs due to a misalignment of the eyes, blocking the view of one eye should improve a person’s sight.

Cause of Condition

Double vision can be caused by an abnormality in the eye itself, a disease in other parts of the body that also affects the eyes, or a head injury that has affected the brain’s ability to process the signals from the eyes. Common causes are:

  • Cornea problems such as corneal scars and cornea dryness
  • Diseases such as shingles and herpes zoster
  • Lens problems due to cataracts
  • Weakness in the muscles of one or both eyes
  • Diseases such as Myasthenia Gravis and Grave’s Disease
  • Diseases that affect the nerves in the brain or spinal cord such as multiple sclerosis
  • Disorders of the brain, such as a stroke or aneurysms
  • Head injuries

Key Symptoms

Double vision can be accompanied by other symptoms, such as:

  • Headaches
  • Pain in the temple area
  • Nausea
  • Weakness of the eyes
  • Droopy eyelids
  • Sudden weakness of the face, arms, and legs
  • Difficulty speaking
  • Dizziness
  • Loss of balance

If double vision is caused by aneurysms or stroke, symptoms will include sudden extreme headaches, stiff neck, loss of consciousness, seizure, dropping eyelid, and nausea or vomiting. The condition requires immediate medical attention as it is life-threatening.

Who to See & Types of Treatment Available

Patients who are experiencing double vision should consult their primary care physician for a diagnosis. Depending on the findings, they may be referred to other specialists such as neurosurgeons and ophthalmologists. To make a diagnosis, the attending physician will inquire about the symptoms and when they first occurred. The patient’s medical history and history of diseases in the family will also be reviewed. This is followed by a thorough physical examination to assess eye function to determine if double vision is due to an abnormality of the eye itself or if it’s caused by a disease that affects the nerves.

Certain diagnostic imaging tests, such as an MRI, may be performed to assess the condition and identify other possible causes.

Meanwhile, the treatment will depend on the underlying cause.

  • For double vision that is caused by a refractive error, treatment will include wearing prescription eyeglasses or contact lenses. Some eye problems, such as cataracts, will require surgery.

  • If stroke, aneurysm, trauma, and cancers cause the condition, the treatment usually involves surgery.

  • Olitsky SE, Hug D, Smith LP. Disorders of vision. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 613.

  • Thurtell MJ, Tomsak RL. Vision loss. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta JC, eds. Bradley's Neurology in Clinical Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 14.

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